I am using 2.5.0 with Internet Explorer 11 in Windows 8.1 Pro 64-bit. I have found out at least 3 bugs:
(1) When you are signing up for a new site and enter your password, the LP sign-in window pops up after every single character. So you type "x", the windows pops up, and you have to cancel it before you can type the next character;
(2) Sometimes when you select a website in LP, it signs you out when you arrive. For example, I was just signed into LP, choose these forums, and when my browser arrived, I was signed out; and
(3) Similar to (2) above, sometimes I am signed into LP and then navigate (not through LP, but through search, IE Favorites, etc.) to another website and LP signs me out.